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Q11910: PRB: SIZE Operator Value

Article: Q11910
Product(s): Microsoft Macro Assembler
Version(s): 4.0,5.0,5.1,6.0
Operating System(s): 
Keyword(s): 
Last Modified: 06-MAY-2001

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The information in this article applies to:

- Microsoft Macro Assembler (MASM), versions 4.0, 5.0, 5.1, 6.0 
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SYMPTOMS
========

When trying to get the length of a text string, using the SIZE operator can
produce undesired results. In the example below, MSG_LEN is set to a value of 1,
but it seems it should be set to a value of 11:

     MSG DB 'Darth Vader'
     MSG_LEN EQU SIZE MSG

CAUSE
=====

The value of MSG_LEN should be 1. The SIZE operator is defined to be the LENGTH
* TYPE as stated in the documentation. The expression, LENGTH MSG, will be equal
to 1 (when applied to a data label, the LENGTH operator returns the number of
elements created by the DUP operator; otherwise it returns 1) and the
expression, TYPE MSG, will be equal to 1. Therefore, the variable MSG_LEN will
be equal to 1.

RESOLUTION
==========

In Macro Assembler version 6.0, the SIZEOF operator can be used to calulate the
total number of bytes allocated to a data item. In versions prior to 6.0, a
simple way to calculate the value you want is as follows:

     MSG DB 'Darth Vader'
     MSG_LEN EQU $-MSG

Additional query words: 4.00 5.00 5.10 6.00

======================================================================
Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM510 kbMASM600 kbMASM400 kbMASM500
Version           : :4.0,5.0,5.1,6.0

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